Map display terminal and map display method

ABSTRACT

A map display apparatus and a map display method facilitate detection of relationship between the destination (current position) and the peripheral condition even when a detailed map is to be displayed on the narrow display area. The map display terminal displays a particular position, a current position, a destination, on a map by deriving the current position on the basis of a position information from a satellite. The map display apparatus has first means for displaying a wide area map having smaller reduced scale than a detailed map and centered at said current position upon displaying said detailed map centered at said current position.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to a map display terminaland a map display method. More particularly, the invention relates to amap display method for displaying a map corresponding to a currentposition on the basis of a current position information.

[0003] 2. Description of the Related Art

[0004] In the recent years, an apparatus displaying a current positionutilizing a Global Positioning System (GPS) technology has been widelyspreading primarily for vehicular navigation system. In such apparatus,a map data to be displayed is stored in a storage medium, such as CD-ROMor the like so as to display a corresponding map on the basis of acurrent position information obtained by GPS.

[0005] On the other hand, in addition to application for the vehicularnavigation system, a handy type map display terminal has been put intopractical use. Since these apparatus are required to be portable, theapparatus are compact to be impossible to store all of map data, amountof which is huge. Therefore, these apparatus are designed to downloadthe necessary map data by means of communication means.

[0006] As advantage of a system, in which the map data are arranged in amap server on a network and is downloaded as required, the latest mapdata can be constantly provided, and the user may able to obtain thelatest map data constantly. It is also possible to distribute real-timeinformation, such as traffic information or the like by embedding in themap data.

[0007] In case of the handy type map display terminal set forth above,in which the map data is downloaded, portability of such type of the mapdisplay terminal is essential to make a display area narrow to causedifficulty of displaying information of a destination and facilities,such as railway station, intersection and so forth, to be landmarks, inone picture frame. Therefore, when map display is performed taking thedestination (current position) at the center of display, difficulty isencountered in detecting the relationship with the peripheral condition.

[0008] On the other hand, in case of the handy type map display terminalset forth above, until completion of downloading of the map data forinitially displaying the map after completion of downloading, the usermay not be able to check the progress of downloading.

SUMMARY OF THE INVENTION

[0009] Therefore, the present invention has been worked out for solvingthe problems set forth above. It is an object of the present inventionto provide a map display apparatus and a map display method whichfacilitates detection of relationship between the destination (currentposition) and the peripheral condition even when a detailed map is to bedisplayed on the narrow display area.

[0010] Another object of the present invention is to provide a mapdisplay apparatus and a map display method which permits to checkprogress of downloading of detailed map information.

[0011] According to one aspect of the invention, a map display terminalfor displaying a current position on a map by deriving the currentposition on the basis of a position information from a satellite,comprises:

[0012] first means for displaying a wide area map having smaller reducedscale than a detailed map and centered at the current position upondisplaying the detailed map centered at the current position.

[0013] In the preferred construction, the map display terminal furthercomprises second means for displaying the initially displayed wide areamap with expansion in step-by-step manner until the detailed map isdisplayed. The second means may include means for downloading detailedmap information from a server storing the detailed map information.

[0014] The map display terminal may be a portable communicationterminal. In such case, a communication between the portablecommunication terminal and the server is performed through a portabletelephone network. In the alternative, the communication between theportable communication terminal and the server is performed through apacket network.

[0015] The second means may expands display of the wide area map instep-by-step manner depending upon progress of downloading of thedetailed map information. The second means may include means forcalculating an expansion ratio at each display stage on the basis of aratio of reduced scales of the wide area map and the detailed map,number of display stages, progress of downloading.

[0016] According to the second aspect of the present invention, a mapdisplay method for displaying a map of a current position by derivingthe current position on the basis of a position information from asatellite, comprises:

[0017] first step of displaying a wide area map having smaller reducedscale than a detailed map and centered at the current position upondisplaying the detailed map centered at the current position.

[0018] The method preferably further comprises second step of displayingthe initially displayed wide area map with expansion in step-by-stepmanner until the detailed map is displayed. The second step may includesstep of downloading detailed map information from a server storing thedetailed map information. In such case, a communication between theportable communication terminal and the server is performed through aportable telephone network. In the alternative, the communicationbetween the portable communication terminal and the server is performedthrough a packet network. The second step may expand display of the widearea map in step-by-step manner depending upon progress of downloadingof the detailed map information. The second step may include step forcalculating an expansion ratio at each display stage on the basis of aratio of reduced scales of the wide area map and the detailed map,number of display stages, progress of downloading.

[0019] According to the third aspect of the present invention, a storagemedium storing a map display control program for displaying a map of acurrent position by deriving the current position on the basis of aposition information from a satellite, the control program comprising:

[0020] first step of displaying a wide area map having smaller reducedscale than a detailed map and centered at the current position upondisplaying the detailed map centered at the current position.

[0021] The storage medium may further comprise second step of displayingthe initially displayed wide area map with expansion in step-by-stepmanner until the detailed map is displayed.

[0022] Namely, the map display method according to the present inventiondisplays the wide area map centered at a particular position, such asdestination, current position or so forth, with expansion instep-by-step manner depending upon progress of downloading upondownloading the detailed map information from the map server.

[0023] More particularly, in the map display method according to thepresent invention, when the detailed map (reduced scale: large) centeredat the particular position, e.g. the destination or current positiondetected by the GPS in response to the demand of the user, at first,demand for the detailed map data is performed for the map server, and atthe same time, the wide area map (reduced scale: small) preliminarilystored in the terminal is displayed.

[0024] Subsequently, in the map display method according to the presentinvention, the wide area map is displayed with expansion in step-by-stepmanner depending upon the progress of downloading of the detailed mapdata. After completion of downloading, the detailed map is displayed.

[0025] By this, even when the detailed map is displayed on the narrowdisplay area, a relationship between the particular position, e.g.destination or current position and the peripheral condition, can beeasily seen. Also, progress of downloading of the detailed map can alsobe seen easily.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be understood more fully from thedetailed description given hereinafter and from the accompanyingdrawings of the preferred embodiment of the present invention, which,however, should not be taken to be limitative to the invention, but arefor explanation and understanding only.

[0027] In the drawings:

[0028]FIG. 1 is a block diagram showing a construction of one embodimentof a GPS map display terminal with a communication function according tothe present invention;

[0029]FIG. 2 is an illustration showing an order of map display in oneembodiment of the GPS map display terminal according to the presentinvention;

[0030]FIG. 3 is an illustration showing a wide area map data to bestored in ROM of FIG. 1;

[0031]FIG. 4 is a block diagram showing a construction of one embodimentof the map display system according to the present invention;

[0032]FIG. 5 is a flowchart showing a part of a map display process byone embodiment of the map display system according to the presentinvention;

[0033]FIG. 6 is a flowchart showing a part of a map display process byone embodiment of the map display system according to the presentinvention; and

[0034]FIG. 7 is a block diagram showing a construction of anotherembodiment of the map display system according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035] The present invention will be discussed hereinafter in detail interms of the preferred embodiment of the present invention withreference to the accompanying drawings. In the following description,numerous specific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be obvious, however, tothose skilled in the art that the present invention may be practicedwithout these specific details. In other instance, well-known structureare not shown in detail in order to avoid unnecessary obscurity of thepresent invention.

[0036]FIG. 1 is a block diagram showing a construction of one embodimentof a map display terminal according to the present invention. In FIG. 1,one embodiment of the map display terminal according to the presentinvention is constructed with a central processing unit (CPU) 1, aread-only-memory (ROM) 2, a random-access memory (RAM) 3, acommunication block 4, a display block 5 and a GPS block 6.

[0037] CPU 1 performs control of overall system including control of thecommunication block 4, the display block 5 and the GSP block 6 accordingto programs stored in ROM 2. ROM 2 stores the programs for operating thesystem and a wide area map data (reduced scale: small). RAM 3 is used asa work area.

[0038] The communication block 4 is constructed with a modem 41 and aportable radio telephone portion 42 for forming means for establishingconnection with an internet using a portable telephone network. Thedisplay block 5 is constructed with a LCD controller (Liquid CrystalDisplay Controller) 51 and an LCD 52. The LCD controller 51 performsdata display, such as map display or the like, on the LCD 52 undercommand from CPU 1.

[0039] The GPS block 6 is constructed with a GPS decoder 61 and a GPSradio communication portion 62 for receiving a radio wave broadcastedfrom a GPS satellite (not shown) and notifying the current position, aslatitude and longitude information to CPU 1.

[0040]FIG. 2 is an illustration showing an order of map display in oneembodiment of the map display terminal according to the presentinvention. In FIG. 2, upon displaying a detailed map (reduced scale:large) around a destination (current position measured by GPS) accordingto a demand of the user, CPU 1 performs a detailed map data demand to amap server from a communication block 4, at first. At the same time, thewide area map (reduced scale: small) which is preliminarily provided inROM 2, is displayed in the display block 5.

[0041] Subsequently, CPU 1 expands display of the wide area map instep-by-step manner according to progress of downloading of the detailedmap data. Namely, CPU 1 performs expanded display of the wide area mapof level 1 when 33% of downloading is completed, for example, expandeddisplay of the wide area map of level 2 when 66% of downloading iscompleted, and the detailed map display when 100% of downloading iscompleted.

[0042]FIG. 3 is an illustration showing the wide area map data stored inROM 2 of FIG. 1. FIG. 3 shows that, as the wide area map data stored inROM 2, when latitude and longitude data is applied, a map data in bitmapformat adapting to the size of a display area of the LCD and centered atthe location identified by the latitude and the longitude data isobtained. On the other hand, upon displaying the map data, the mapdisplay terminal can display the map at arbitrary reduced scale.

[0043]FIG. 4 is a block diagram showing one embodiment of a map displaysystem according to the present invention. In FIG. 4, one embodiment ofthe map display system according to the present invention is constructedwith the GPS map display terminal 10 with the communication function, abase station 11, a portable telephone network 12, an internet serviceprovider (ISP) access point 13, an internet 14 and a detailed map server15.

[0044] The GPS map display terminal 10 with the communication functioncan access the internet 14 by establishing connection with the ISPaccess point 13 through the base station 11 and the portable telephonenetwork 12. On the other hand, the GPS map display terminal 10 with thecommunication function has the same construction as the map displayterminal shown in FIG. 1.

[0045] It should be noted that the base station 11, the portabletelephone network 12, the ISP access point 13 and the internet 14 havethe same constructions as those been practiced conventionally.Therefore, detailed description for these components will not bediscussed.

[0046] The detailed map server 15 is a typical web server connected tothe internet 14 and can transfer the detailed map data or the likeaccording to HTTP (Hyper Text Transfer Protocol).

[0047] The detailed map server 15 holds more detailed map data than thewide area map stored in ROM 2 in the GPS map display terminal 10 withthe communication function. A map format of the detailed map isequivalent to that of the wide area map stored in ROM 2. The detailedmap server 15 is responsive to a demand for the detailed map from theGPS map display terminal 10 with the communication function bydesignating latitude and longitude of the arbitrary location, to providethe detailed map data centered at the location identified by the appliedlatitude and longitude to the GPS map display terminal 10 with thecommunication function.

[0048] In general, detailed map is necessary in the city and not sodetailed map is required in mountainous area or so forth. Even in theshown embodiment of the system, the reduced scale of the detailed mapprovided by the detailed map server 15 is different at different area.Namely, a ratio between the reduced scale of the wide area map stored inROM 2 and the reduced scale of the detailed map provided by the detailedmap server 15 is also different at different area.

[0049] The detailed map server 15 is responsive to designation of thelatitude and longitude from the GPS map display terminal 10 with thecommunication function and demand for the reduced scale ratio, toprovide the ratio of reduced scale (magnification) between the detailedmap data centered at the location identified by the latitude andlongitude and the wide area map data, to the GPS map display terminal 10with the communication function.

[0050]FIGS. 5 and 6 are flowcharts showing the map display process to beperformed by one embodiment of the map display system according to thepresent invention. The map display process according to one embodimentof the map display system according to the present invention will bediscussed with reference to FIGS. 1 to 6. The operation for displayingthe detailed map centered at the current position on the basis of theGPS position information will be discussed hereinafter. The processshown in FIGS. 5 and 6 can be realized by executing the program storedin ROM 2 by CPU 1.

[0051] CPU 1 of the GPS map display terminal 10 with the communicationfunction, at first, performs wide area map display centered at thecurrent position on the basis of the GPS position information (latitude,longitude) (step S1 of FIG. 5). Here, the wide area map data stored inROM 2 is displayed as it is without expansion (magnification of 1).

[0052] CPU 1 sets number of division (number of steps upon performingexpanded display) to a parameter Y (step S2 of FIG. 5). In case of theexample of the map display shown in FIG. 2, at a timing where theprogress of downloading is 33% and at a timing where the progress ofdownloading is 66%, the wide area map is displayed with progressivelyexpanding in step-by-step, and at a timing where the progress ofdownloading is 100%, the detailed map is displayed.

[0053] Namely, in order to perform three steps of expanding display fromthe initial wide area map display, number of division in this casebecomes three. For example, in case of number of division is four, themap display will be updated at timings of progress of downloading at25%, 50% 75% and 100%. Setting of number of division may be setpreliminarily by the user.

[0054] CPU 1 requires magnification X of the reduced scale of thecorresponding detailed map data with respect to the wide area data onthe basis of the latitude and longitude data to the detailed map server15 (step S3 of FIG. 5), and sets a magnification value returned from thedetailed map server 15 to a parameter X (step S4 of FIG. 5). In thisdisclosure, the magnification means the ratio of the reduced scales ofthe wide area map and the detailed map. For instance, when the reducedscale of the wide area map is 1/50000 and the reduced scale of thedetailed map is 1/25000, the magnification X becomes two (2).

[0055] After receiving the magnification value, CPU demands the detailedmap data corresponding to the latitude and longitude data with respectto the detailed map server 15 (step S5 of FIG. 5) and then enter intooperation for expanded display for expanding the wide area map accordingto the progress of downloading until downloading is completed.

[0056] Upon performing operation for expanded display, CPU 1 at firstsets a counter parameter i to 0 (step S6 of FIG. 5). Next, the counterparameter i is incremented by 1 (i=i+1) (step S7 of FIG. 6).

[0057] At this state, the system enters into downloading progresswaiting state of the detailed map data (step S8 of FIG. 8). For example,in case that number of division is three, judgment of branching becomes“YES” at the downloading progress of 33%, 66% and 100%. HTTP is used fordownloading. In this method, since the size of the file is initiallytransferred, the progress can be easily calculated by comparing thetransferred file size and the actually downloaded data amount.

[0058] If the result of judgment of the condition is “YES”, CPU 1 makesjudgment whether the progress of downloading is 100% or not (step 9 ofFIG. 6). If the result of judgment at step S9 is “NO”, the wide area mapis displayed with expansion at a magnification derived by:

X*i/Y

[0059] (step S10 of FIG. 6). For example, when number of division isthree and a ratio of reduced scale of the detailed map versus thecontraction scale of the wide area map is four, the wide area map isexpanded to 1.3 times when the downloading progress is 33%, and to 2.6times when the downloading progress is 66%.

[0060] CPU 1 repeats the procedure from step S7 to step S10 until thedownloading progress becomes 100%. Once, downloading is completed, thedetailed map is displayed (step S11 of FIG. 6). Then, process goes end.

[0061] As set forth above, by initially displaying the wide area map(reduced scale: small) stored in ROM 2, even when the detailed map isdisplayed in narrow display area, it can be easily perceived therelationship between the destination (current position) and theperipheral condition.

[0062] On the other hand, by displaying the initially displayed widearea map with progressively expanding in step-by step manner dependingupon downloading progress of the detailed map data, progress ofdownloading of the detailed map data can be easily appreciated.

[0063]FIG. 7 is a block diagram showing a construction of anotherembodiment of the map display system according to the present invention.In FIG. 7, another embodiment of the map display system is constructedwith the GPS map display terminal 10 with the communication function,the base station 11, a packet network 16, a gate way 17 of the packetnetwork, the internet 14 and the detailed map server 15.

[0064] In the former embodiment of the map display system according tothe present invention, the system takes a construction, in which theinternet 14 is accessed by establishing connection with the ISP accesspoint 13 by circuit connection. In the recent years, since packetswitching service utilizing radio infrastructure for the portabletelephone has been available, it is possible to employ a construction toestablish connection with the internet 14 using this service.

[0065] In the shown embodiment of the map display system according tothe present invention, the foregoing construction has been taken toestablish connection between the packet network 16 and the internet 14through the packet network gate way 17. In the shown embodiment of themap display system according to the present invention, since only meansfor accessing the internet 14 is modified, other portions are similar tothe former embodiment of the map display system according to theinvention.

[0066] On the other hand, while, in the former embodiment of the mapdisplay system according to the present invention, the wide area mapdata is stored in ROM 2 in the GPS map display terminal 10 with thecommunication function, it is also possible to construct the system fordownloading the wide area map per se from the detailed map data. In suchcase, since map data is not provided in the terminal, further downsizingof the terminal can be permitted. However, since the wide area map hasto be downloaded initially, it inherently take longer period forinitially displaying the wide area map.

[0067] Furthermore, while the former embodiment of the map displaysystem according to the present invention employs the bit map format asthe data format of the map, a vector system may also be employed. Thevector system is a data format storing information of road, groundprofile and so forth as aggregate of lines on the basis of thecoordinate data. The map display method according to the presentinvention can be realized when it permits expanded display of the map,no map data format is specified or restricted.

[0068] As set forth above, with the map display terminal according tothe present invention, when the current position is displayed on the mapby deriving the current position on the basis of the positioninformation from a satellite, upon displaying the detailed map centeredto the current position, a relationship between the destination (currentposition) and the peripheral condition can be easily seen even when thedetailed map is to be displayed in the narrow display area by displayingthe wide area map centered to the current position.

[0069] On the other hand, with another embodiment of the map displayterminal according to the present invention, by displaying the wide areamap with expansion of the initially displayed wide area map instep-by-step until the detailed map is displayed, progress ofdownloading of the detailed map can be seen easily.

[0070] Although the present invention has been illustrated and describedwith respect to exemplary embodiment thereof, it should be understood bythose skilled in the art that the foregoing and various other changes,omission and additions may be made therein and thereto, withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be understood as limited to thespecific embodiment set out above but to include all possibleembodiments which can be embodied within a scope encompassed andequivalent thereof with respect to the feature set out in the appendedclaims.

What is claimed is:
 1. A map display terminal for displaying a currentposition on a map by deriving the current position on the basis of aposition information from a satellite, comprising: first means fordisplaying a wide area map having smaller reduced scale than a detailedmap and centered at said current position upon displaying said detailedmap centered at said current position.
 2. A map display terminal as setforth in claim 1, which further comprises second means for displayingthe initially displayed wide area map with expansion in step-by-stepmanner until said detailed map is displayed.
 3. A map display terminalas set forth in claim 2, wherein said second means includes means fordownloading detailed map information from a server storing said detailedmap information.
 4. A map display terminal as set forth in claim 3,which is a portable communication terminal.
 5. A map display terminal asset forth in claim 4, wherein a communication between said portablecommunication terminal and said server is performed through a portabletelephone network.
 6. A map display terminal as set forth in claim 4,wherein a communication between said portable communication terminal andsaid server is performed through a packet network.
 7. A map displayterminal as set forth in claim 3, wherein said second means expandsdisplay of said wide area map in step-by-step manner depending uponprogress of downloading of said detailed map information.
 8. A mapdisplay terminal as set forth in claim 4, wherein said second meansincludes means for calculating an expansion ratio at each display stageon the basis of a ratio of reduced scales of said wide area map and saiddetailed map, number of display stages, progress of downloading.
 9. Amap display method for displaying a map of a current position byderiving said current position on the basis of a position informationfrom a satellite, comprising: first step of displaying a wide area maphaving smaller reduced scale than a detailed map and centered at saidcurrent position upon displaying said detailed map centered at saidcurrent position.
 10. A map display method as set forth in claim 9,which further comprises second step of displaying the initiallydisplayed wide area map with expansion in step-by-step manner until saiddetailed map is displayed.
 11. A map display method as set forth inclaim 10, wherein said second step includes step of downloading detailedmap information from a server storing said detailed map information. 12.A map display method as set forth in claim 11, wherein a communicationbetween said portable communication terminal and said server isperformed through a portable telephone network.
 13. A map display methodas set forth in claim 11, wherein a communication between said portablecommunication terminal and said server is performed through a packetnetwork.
 14. A map display method as set forth in claim 11, wherein saidsecond step expands display of said wide area map in step-by-step mannerdepending upon progress of downloading of said detailed map information.15. A map display method as set forth in claim 14, wherein said secondstep includes step for calculating an expansion ratio at each displaystage on the basis of a ratio of reduced scales of said wide area mapand said detailed map, number of display stages, progress ofdownloading.
 16. A storage medium storing a map display control programfor displaying a map of a current position by deriving said currentposition on the basis of a position information from a satellite, saidcontrol program comprising: first step of displaying a wide area maphaving smaller reduced scale than a detailed map and centered at saidcurrent position upon displaying said detailed map centered at saidcurrent position.
 17. A storage medium as set forth in claim 16, whichfurther comprises second step of displaying the initially displayed widearea map with expansion in step-by-step manner until said detailed mapis displayed.